An aircraft typically comprises a fuselage, wings, and engines. Each engine comprises internal engine components (e.g., turbofan components) and a nacelle which houses the internal engine components. Each nacelle includes an inlet lip which defines the inlet opening through which air enters the engine. The formation of ice on the nacelle inlet lip can be a common occurrence during the flight of an aircraft. Ice build-up on the lip can change the contour of the engine's air inlet, thereby adversely affecting air flow patterns (e.g., constricting air flow into the engine) and aerodynamic characteristics (e.g., increasing drag). Moreover, if large pieces of ice break free from the inlet lip and enter the engine, they can damage rotor blades and other internal engine components. Accordingly, it is usually necessary for an aircraft to include some type of nacelle ice protection system.